Treatment sequence in castration-resistant prostate cancer: A retrospective study in the new anti-androgen era

Taxane-based Chemotherapy Induced Androgen Receptor Splice Variant 7 in Patients with Castration-Resistant Prostate Cancer: A Tissue-based Analysis

In total, 95 prostate cancer (Pca) patients who underwent transurethral resection of the prostate from 2000 to 2013 were assigned to four groups: Group 1, hormone-naïve and T1a or T1b Pca (n = 17); Group 2, hormone-sensitive and metastatic Pca (n = 33); Group 3, chemo-naïve castration-resistant Pca (CRPC), (n = 18); and Group 4, CRPC with chemotherapy (n = 27). Full-length androgen receptor (ARfl) transcript levels significantly increased from Group 1 through to Group 3 (p = 0.045), but decreased from Group 3 through to Group 4. AR splice variant 7 (ARV7) and glucocorticoid receptor (GR) transcript levels significantly increased from Group 1 through to Group 4 (p = 0.002 and 0.049, respectively). Kaplan-Meier curve revealed that the high transcript level of these three receptors resulted in significantly poorer cancer-specific survival (CSS) than that by low transcript level, although Cox regression analysis revealed that the ARV7 level alone was an independent prognostic factor for CSS in CRPC patients (high vs. low: hazard ratio, 1.897; 95% confidence interval, 1.102-3.625; p = 0.042). In conclusion, ARV7 and GR transcript levels significantly increase as Pca progresses to CRPC.

Clinical Outcomes of First-line Abiraterone Acetate or Enzalutamide for Metastatic Castration-resistant Prostate Cancer After Androgen Deprivation Therapy + Docetaxel or ADT Alone for Metastatic Hormone-sensitive Prostate Cancer

BACKGROUND

The CHAARTED (ChemoHormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer) and STAMPEDE (Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy) trials showed that the addition of docetaxel (D) to androgen deprivation therapy (ADT) prolonged longevity of men with metastatic hormone-sensitive prostate cancer (mHSPC). However, the impact of upfront D on subsequent therapies is still unexplored. As abiraterone acetate (AA) and enzalutamide (E) are the most commonly used first-line treatment for metastatic castration-resistant prostate cancer (mCRPC), we aimed to assess whether they maintained their efficacy after ADT+D versus ADT alone.

PATIENTS AND METHODS

A cohort of patients with mCRPC treated between 2014 and 2017 with first-line AA or E for mCRPC was identified from 3 hospitals' institutional review board-approved databases. Patients were classified by use of D for mHSPC. This time frame was chosen as ADT+D became a valid therapeutic option for mHSPC in 2014, and it inherently entailed a short follow-up time on AA/E. The endpoints included overall survival from ADT start, overall survival from AA/E start, and time to AA/E start from ADT start. Differences between groups were assessed using the log-rank test.

RESULTS

Of the 102 patients with mCRPC identified, 50 (49%) had previously received ADT alone, while 52 (51%) had ADT+D. No statistically significant difference in any of the evaluated outcomes was observed between the 2 cohorts. Yet, deaths in the ADT+D group were 12 versus 21 in the ADT alone, after a median follow-up of 24.4 and 29.8 months, respectively.

CONCLUSION

In a cohort of ADT/ADT+D-treated patients with mCRPC with short times to first-line AA/E and follow-up, the efficacy of AA/E is similar regardless of previous use of D.